1. Field of the Invention
The present invention relates to a method of forming carbon nanotube emitters and a method of manufacturing a field emission display including such carbon nanotube emitters, and more particularly, to a method of forming impurity-free carbon nanotube emitters using a simple process and a method of manufacturing a Field Emission Display (FED) device including such carbon nanotube emitters.
2. Description of the Related Art
Typical applications of display devices as important information transfer media include monitors for personal computers and television screens. The display devices include Cathode Ray Tubes (CRTs) which use thermionic emission at high speed and flat panel displays. Flat panel displays include Liquid Crystal Displays (LCDs), Plasma Display Panels (PDPs), and Field Emission Displays (FEDs).
An FED is a display device in which electrons are emitted from a field emitter arranged at regular intervals on a cathode electrode by forming a strong electric field between the field emitter and a gate electrode and light is radiated when electrons collide with a fluorescent material of an anode electrode.
A micro-tip formed of a metal such as Molybdenum (Mo) is widely used as the field emitter. However, Carbon Nanotube (CNT) emitters are now being used. Since an FED using CNT emitters has advantages including a wide viewing angle, a high resolution, a low power consumption, and temperature stability, FEDs using CNT emitters are very suitable for car navigation devices or viewfinders for electronic image display devices. Also, an FED using CNT emitters can be used as a replaceable display device for a personal computer, a Personal Data Assistant (PDA), a medical apparatus, or a high definition television. It can also be used as a backlight for an LCD.
There are two methods of forming a CNT emitter. A first method forms the CNT emitter by growing the CNT on a substrate, and a second method forms the emitter mechanically by making a CNT paste.
When using the first method, it is difficult to form a large device because the CNT must be grown on a substrate. Also, when glass is used as the substrate, a high temperature can become a problem depending on the method of growing.
On the other hand, when using the second method, an impurity such as a binder, a resin, or a filler can be included in the pure carbon nanotubes during forming the emitter mechanically. It is known that the impurity negatively affects the lifetime and stability of the carbon nanotube emitter. Also, a number of defects during a purifying process of the carbon nanotubes can occur. These defects can also reduce the lifetime of the carbon nanotube.